Testing apparatus for automotive brakes



f-nf@ 3G, 31%@ w. E. CUNNINGHAM 2,046,018

TESTING APPARATUS FOR AUTOMOTIVE BRAKES Filed Nov. 12, 1954 PatentedJune Si?, i936 Uiiii STATES PATENT OFFICE TESTING APPARATUS FORAUTOMOTIVE BRAKES 2 Claims.

My invention relates to a testing apparatus for use in connection withthe testing of brakes of automobiles, and has for its primary object theprovision of an apparatus which is adapted to be secured to the wheelsof the automobile after they hare been jacked up or otherwise held freeof the ground or floor, and force applied thereto through the wheelwhile the brakes are applied, in such manner that the force necessary toturn wheel, while the brakes are applied, is registered through thedevice. By applying the device to the various wheels of the automobileit will be possible, therefore, to adjust the brakes in such manner thatthe braking force applied to each wheel is equal.

Another and further object of my invention is the provision of a devicewhich is simple to operate, is comparatively cheap to manufacture, andwhich can be utilized by small garages, individual car owners, and thelike, for the purpose of testing brakes should they desire to do so, andadjust them themselves.

Another and further object is the provision of a device which is soconstructed that when applied to an automobile wheel the application offorce through the device and turning movement is uniform in each istance, thereby attaining uniform results in testing the brake forcewhich is being applie to the brake drums of the automobile through thenormal operation of the brakes themselves.

These and other objects of my invention will be more fully and betterunderstood by reference to the accompanying sheet of drawings and inwhich- Figure l is a front elevational View of my improved invention;

Figure 2 is a sectional view on line 2 2 of Figure l; and

Figure 3 is a detailed View showing the operation of the registeringdevice secured to the apparatus.

Referring now specifically to the drawing and in which like referencecharacters refer to like parts throughout, a casing iii is shown havinga frusto-conical recess in one side thereof, with a lining l2 of anysuitable material, such as fabric, rubber or the like, to preventcontact with the metal surfaces of the device upon the hub cap of theautomobile. The recess H is of such type that the member l0 can easilybe centered with respect to the hub cap |3 of an automobile wheel,thereby insuring that a force applied to the wheel for turning thereof,as will be hereinafter described, is uniform for each Wheel.

The casing has a recess Hl on the outer face thereof and has a shaft |5,the outer end I6 of which is preferably octagonal in shape and adaptedto be received in an octagonal shaped opening l? and the handle memberI8, by means of which the device is turned when in operation.

Mounted in the recess |ll on the shaft I5 is an eccentric cam i9 whichis adapted to rotate with the shaft l5. At one side of the casing I3 isa tubular extension 20 secured to the main casing by bolts 2|, 2| andhaving an end cap 22 secured thereto or made integral therewith, as maybe desired, and having a helical spring 23 mounted therein, the lowerend of which is in engagement with a washer 2li adapted to seat in arecess formed in the upper side of the casing I0. Mounted in the tubularextension 2D and having its lower end extending into the recess ill, isa push rod 25 having an enlarged head 2l at the lower end thereofadapted to engage with the eccentric cam i9, and having a reduced upperend portion with an annular shoulder 28 formed thereon intermediate itsends adapted to engage the Washer 2li on the under side thereof wherebythe spring 23 is compressed by the upward movement of the push rod 25.

Mounted on the cap 22 at the upper end of the device is a pressureregistering mechanism comprising a dial 29 having appropriate indiciathereon graduated in such manner as to indicate pressure as measured bythe compression of the spring 23. The dial is mounted upon a blockmember 30 having a casing 3| mounted therein upon which a small gearwheel 32 is mounted having a hub portion 33 in the outer end of which aratchet notch 34 is formed within which a pin 35, which extends througha shaft 36, is mounted. On the outer end of the shaft 3S is a small ngerWheel 3l for resetting the indicator hand, as hereinafter described. Thewheel 32 is slidingly mounted upon the shaft 34 and is normally held inoutward position by a helical spring 38. On the opposite end of theshaft an indicating hand 33 is mounted which in normal operativeposition of the device is set at zero, The upper end of the push rod 26has teeth 43, formed thereon adapted to normally engage in the gearwheel 32 for the purpose of rotating the indicator hand 35 to indicatethe pressure applied to the device during its operation.

Attached to two corners of the casing I0 is a pair of links 4|, 4|,these links being hinged to the casing l0 by means of pins 52. 42 whichpass through the ends of the links 4|, bent in 2 Y Y 4 aoeaole 44 to thecasing I in the same mannerias is described for the links 4i,these-links being similar to links 4I except that theyT are considerablyshorter in length. Y

Secured to the outer ends of the links 43, 43 are other links 45, withtoggle members 46, 46

being secured to the members 43 and 45 respec- Y tively, by means ofwhich, after the device is adjusted around the tire 41 of an automobilewheel, the toggles arefclosed, thereby clamping the device onto theautomobile wheel. For this purpose there is secured to the outer ends ofeach of the links 4i and 45', grip members 48 having curved end portions43 adapted to conform generally to the curvature of an automobile tire41.

On the inner ends of the members 48 are loops 55 through which the links44 and 45 on each of the grips ,areadapted to extend, these membershaving holes 5I, 5I therein into which pins 52, 52, xedgin each of themembers 48, are adaptedglto be received for the purpose of making aninitial adjustment of the device to conform tovariefus size automobileWheels. In adjustingy these grip members, when the device is removedfrom the tire it is necessary only to turn the members 48 away4 fromYthe members 4I and 45 respectively, sethat the pins 52 are disengagedfrom the holes 5l, and the grips 48 can thereupon be adjusted to anydesiredY position as the device is applied to an automobile wheel.VAfter this initial adjustment is made the toggle-members are placed inone position, and when they are closed the links 45 are drawn inward;thereby effectively clamping the device onto anV automobile wheel.

In operation of the device, the automobile preferably is jacked orotherwise lifted free of the Vground or floor so that the wheels can befreely rotated, and whatever brake pressure may be necessaryapplied-thereto by means of an app-ropr'iate jack placed against thebrake pedal, or Y Y the pedal can be held down in any approved manner aslong as it is held in any predetermined posi- Y tion suiiciently toapply the brakes as much as may be desired. The device isthereuponapplied to an automobile wheel as heretofore described, byr placing thegrip members over the tire and clamping them in position, with thecasing I@ centered over the hub cap of the wheel. In its normal positionthe cam I9 is in its lowermost position, as shown in Figure 1 of theydrawing. handle I8 isvthereupon applied tothe end IS of the shaft I5 anda turning force applied thereto, preferably in the normal direction inwhich the automobile wheel turns, and a continued turning movementrotates the eccentric memberV I9, placing the helical spring 23 undercompression until the resistance of the turning movement of the wheel bythe brakes is overcome by the force exerted by the helical sprmg'uponthe eccentric member I9, at which point1 the wheel will begin to move. l

In the meantime the teeth 40, 40 engaging with the wheel 32 rotate theindicator hand 39 to a point on the dial where the force applied to thewheel is registered. The haridle I8 is thereupon released and theeccentric cam I9 returned to its normal position.Y The wheel. 32compresses the spring. 38 and slides out of engagement Withthe p-in 35and the device returns to normal position, leaving the indicato-i hand39 at its maximum point of indication en the dial. 'Ihe hand may be leftset at this point and the device applied to 10 another wheel until theforce is equal to that measured upon this wheel, or the mechanic maynote the foree applied to this wheel, whereupon by turning the-Wheel 31the indicator hand 39 is returned tots zero position. l In this mannerthe device is applied to each of the wheels of the automobileV andbraking force tested, and-the necessary adjustment made in the Ybrakesto insure uniform braking force being applied equally to all of theautomobile wheels'. It 20 will be noted that the eccentric member IE canbe turned in either direction so that the device canV be applied toautomobile wheels on either side of the car, Vbut at the same Ytime itis so placed that the device cannot bel turned to make 2 a completerevolution of the cam I g, thereby re- -sulting in possible injury tothe oerator of the device. Y,

While I have described more or'less precisely the details-ofconstruction,V I do not wish to'be 3 understood as limiting myselfthereto, as I contemplate changes in form and the proportion of partsand the substitutiong'of equivalents as circumstances may suggestlorrender expedient Without departing from the spirit or scope of myinvention.

I claim: i

1. Apparatus foi;` .testing brakes of automotive vehicles, comprising acasing having a frustoconical recess in one side thereof, a plurality of4' tire-gripping members secured at their inner ends l to said casingand having `curved outer ends for engagement with an automobile tire, ashaft in said casing, a rotatable cam in said casing eccentricallirmounted on said shaft, a push rod in i i said casing extending into thepath of rotation of said cam whereby the said cam is prevented frommaking a complete revolution, a spring on said push rod, indicatingmeans actuated by said push rod, and a handle adapted to engage the said5 shaft on its outer end.

2. Apparatus for testing brakesof automotive vehicles, comprising acasing having a frustoconical recess in one side thereof, a plurality oftire-gripping arms secured at their inner ends to 5 said casing havingcurved outer ends, one pair of said arms having toggle connectionsintermediate their ends, `a shaft in said casing, a rotatable cam insaid casing eccentrically mounted on said shaft, a push rod on'saidcasing extending into 6 the path Yof rotation of said cam whereby thesaid Y cam is prevented from making a complete revolution, a spring onsaid push rod, indicating means actuated by said push rod, andV a handleadapted to engage the said shaft on its outer end. 6

